Combined potentiometer and switching structure

ABSTRACT

A combined potentiometer and switching structure including wiper contacts fixed to a shaft and having contacting engagement with an annular resistor and a pair of switching rings. The wiper contacts are located coincident, or in phase relation. The switching rings are each provided with an interrupted area, such areas are located in an arc complemental to the arc of the resistor and are circumferentially spaced apart a distance not greater than the length of the resistor contacting surface whereby, during rotation of the shafts, circuits connected to the switch rings are opened at different positions with respect to the resistor wiping contact. alignment openings in the rings accommodate a pin to permit proper positioning of the rings relative to one another and also provide a passage for a conductor upon removal of the pin once the rings are properly positioned and secured against displacement.

Tygard et al.

[ COMBINED POTENTIOMETER AND SWITCHING STRUCTURE [75] Inventors: CharlesM. Tygard; James H.

Cameron, both of West Covina, Calif.

[73] Assignee: Spectrol Electronics Corporation,

City of Industry, Calif.

[22] Filed: Jan. 12, 1973 [21] Appl. No.: 323,188

Related U.S. Application Data [62] Division of Ser. No. 54,045, June 1,1970, Pat. No. 3,679,848, which is a division of Ser. No. 828,617, May28, 1969, Pat. No. 3,585,562.

[52] US. Cl. 200/8 A, 200/155 R, 338/172 [51} Int. Cl. H0lh 19/58 [58]Field of Search 200/155 R, 11 A, 11 D, 200/166 BB, 8 R, 8 A; 338/296,304, 172

[56] References Cited UNITED STATES PATENTS 2,233.113 2/1941 Smith. Jr200/8 A 3.112.377 ll/l963 Andela ZOO/ll l) 3,135,840 6/1964 Ausfeld200/8 A 1 Jan. 28, 1975 Primary Examiner-Robert K. Shaefer AssistantExaminer-William J. Smith Attorney, Agent, or Firm-J. Raymond Curtin;Frank N. Decker, Jr.

[57] ABSTRACT A combined potentiometer and switching structure includingwiper contacts fixed to a shaft and having contacting engagement with anannular resistor and a pair of switching rings. The wiper contacts arelocated coincident, or in phase relation. The switching rings are eachprovided with an interrupted area, such areas are located in an arccomplemental to the arc of the resistor and are circumferentially spacedapart a distance not greater than the length of the resistor contactingsurface whereby, during rotation of the shafts. circuits connected tothe switch rings are opened at different positions with respect to theresistor wiping contact. Alignment openings in the rings accommodate apinto permit proper positioning of the rings relative to one another andalso provide a passage for a conductor upon removal of the pin once therings are properly positioned and secured against displacement.

1 Claim, 6 Drawing Figures P ATENTED B SHEET 10F 3 FIG. 5

COMBINED POTENTIOMETER AND SWITCHING STRUCTURE This is a division, ofapplication Ser. No. 54,045 filed June 1, 1970, now U.S. Pat. No.3,679,848 which in turn is a division of application Ser. No. 828,617,filed May 28, 1969, now U.S. Pat. No. 3,585,562.

BACKGROUND OF THE INVENTION A combined potentiometer-circuit switchingunit has been proposed wherein a common rotor supports both the switchactuator and the wiping contact for engaging the resistance coil of thepotentiometer. When additional circuit switching functions are required,the housing becomes undesirably bulky. It has been suggested that acommon mounting ring be employed for supporting two switching units.While such an arrangement will conserve space by reducing the length ofthe housing required, a simple inexpensive method of assembling theparts so that conductors located in inaccessible locations may bereadily connected to the switch units is needed.

SUMMARY OF THE INVENTION This invention has to do with a combinedpotentiometer and circuit switching structure. The potentiometer is ofthe conventional annular type having a circular contacting surfaceengaged by a wiping contact fixed to a shaft. A second wiper contact isaffixed to the shaft and is phased with the resistor wiper contact. Thissecond contact engages a pair of conducting switch rings. A circuit isformed from the second wiper contact through each of the switch rings.The switch rings are formed with interrupted areas whereby, at differentpositions of the resistor wiper contact, the switching circuits areopened.

More particularly, the invention is directed to a structural arrangementwhich is economical to manufacture and convenient to assemble to producea device having very small overall dimensions.

In addition, the invention relates to a unique method of assembling theswitch rings in the switch insulator whereby welding of electrical leadsto the switch rings may be easily accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of astructure embodying our invention;

FIG. 2 is an end elevation looking to the right, FIG.

FIG. 3 is an enlarged sectional view taken on a line corresponding toline 3-3, FIG. 2.

FIG. 4 is a sectional view taken on line 4-4, FIG. 3;

FIG. 5 is an exploded view of the switch rings and resistor illustratingthe orientation of such parts; and

FIG. 6 is a schematic diagram illustrating an arrangement of theresistor and switching rings.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus consists ofacasing having sections l0, 11. The section 10 is formed with an end wall12 having an inwardly extending cylindrical hub 13. The hub 13 isprovided with a central aperture forming a bearing in which an enlargedportion 14 of an actuating shaft 15 is journaled.

The casing section 11 is provided with a discoidal closure 16 which isformed with a central aperture arranged in axial alignment with theaperture in the hub 13 and forming a second bearing for the shaft 15.The end member 161s attached to the section 11 by a clamp ring 17.

A resistor 18 of substantially annular configuration is fixedly mountedin the section 11. The inner surface 20 of the resistor is a contactsurface over which a wiper contact 21 is moved. The contact 21 is fixedon one end of an arcuate spring member 22, the opposite end of which isfixed to an arm 23 which, in turn, is fixedly secured to a sleeve 25 ofinsulating material fixedly secured to the shaft 15. A collector ring 27is attached in conductive relation to the arm 23 and is connected to aterminal 28 by a brush 30.

The casing section 10 is formed at its inner end with a cylindricalflange 33 formed with an annular shoulder 34. The casing 11 is formedwith a circular flange 35 snugly engaging the flange 33 and abuttingagainst the shoulder 34. The sections are held together by a clamp ring37;

A pair of switching rings 38, 40 are fixedly mounted in the flange 33 ofthe casing section 10. In the arrangement disclosed, the switching ringsare mounted in an annular insulation member 41, fixedly mounted in theflange 33 and having a flange or central rib 43 extending radiallyinwardly between the switch rings 38, 40. The inner contacting surfacesof the switch rings are engaged by a wiper contact 45 fixed on one endof an arcuate leaf spring member 46, the opposite end of which is fixedto an arm 47 which, in turn, is fixed to the sleeve 25. A collectingring 50 is fixed in conducting relation to the arm 47, and is connectedto a terminal 53 by a brush 54. The collector rings 27, 50 are separatedby a ring of insulating material 55.

The contacting surface 20 of the resistor 18 extends circumferentiallyless than 360 in the structure shown about 325. The switching rings 38,40 are each formed with an interrupted area in their inner contact ingsurfaces. For economy in manufacture, these interrupted areas arepreferably in the form of a notch 58 in ring 38, and a notch 60 in ring40. The switch rings 38, 40 are fixed in the insulating member 41 withthe notches 58, 60 spaced apart circumferentially a distance less thanthe circumferential extent of the effective contacting surface 20 of theresistor 18. It will be apparent rings 38 and 40 are duplicate parts. Toobtain the relationship shown in FIG. 5, it is only necessary to invertone of the rings through an angle of 180.

The switch ring 40 is connected to a terminal by wire 71 convenientlyextended through the apertures 63, 64 in the switching rings and member41, see FIG. 3. The switching ring 38 is connected to a terminal 72 bywire 73. One end of the resistor 18 is connected to a terminal 75 bywire 76. Accordingly, a switching circuit is established from terminal53 to terminal 70 through switching ring 40, and a second switchingcircuit is established through terminal 53 and terminal 72 throughswitch ring 38.

To provide for convenience in assembling the switch rings with theinterrupted areas in the desired phase relation, the rings are formedwith through apertures 63. The member 41 is formed with a throughaperture 64 in the flange or central rib 43. The apertures 63, 64 arealigned and a pin is extended through the apertures. The rings arepressed into the member 41, or otherwise secured therein, and the member41 is pressed or otherwise secured as by applying adhesive material tothe rings prior to the insertion of the pins, in the section 10. Thealignment pin is then removed and the wire 71 is run through theapertures and fixed to the ring 40. The sections 10, 11 are oriented andfixedly clamped together by the band 37.

In FIG. 6, the interrupted areas in the rings 38, 40 are indicated at58, 60 and as being located coincident with the ends of the resistor 18.The wiper contacts 21, 45 are fixed in phase relation, see also FIG. 4.Accordingly, when the resistor wiper 21 is positioned at the right endof the resistor, the contact 45 is in register with the notch 58in theswitch ring 38. When the resistor wiper has been moved to the left endof the resistor, the contact 45 is in registration with the notch 60 inthe switching ring 40. At intermediate positions of the wiper contacts,both switching circuits are energized.

It will be apparent that the interrupted areas of the switching meansmay be phased to provide interruption of the switching circuits atvarious preselected positions of the resistor wiper contact 21.

While we have described a preferred embodiment of our invention, it isto be understood the invention is not limited thereto since it may beotherwise embodied within the scope of the following claims,

We claim:

1. A switch assembly comprising:

l. a casing;

2. a rotary shaft mounted for rotation within said cas- 3. a switchmodule secured with said casing, said switch module comprising:

a. a non-conductive mounting ring mounted coaxially in said casing andhaving an annular rib extending radially inwardly from the inner surfacethereof, said rib having an axially extending locating aperture therein;

b. a first annular metallic switch ring disposed in said mounting ringon one side of said annular rib, said first switch ring having anaxially extending aperture formed therein which is aligned with saidaperture in the annular rib of the mounting during assembly therewith;

c. a second annular metallic switch ring disposed in said mounting ringon the other side of said annular rib, said second annular metallicswitch ring having an axially extending aperture formed therein which isaligned with said aperture in the annular rib of the mounting ringduring assembly therewith;

d each of said annular switch rings having a relieved portion formed onthe inner surface thereof which is positioned in a predeterminedrelationship with the relieved portion of the other switch ring byalignment of said axially extending apertures;

4. a first switch terminal having an electrical conductor extendingtherefrom through the aligned axial apertures in one of said switchrings and said annular rib, said electrical conductor extending into theaperture in the other of said switch rings and being secured inelectrical contact therewith;

5. a second switch terminal having an electrical conductor extendingtherefrom into electrical contact with said one switch ring; and

6. a spring biased wiper contact carried by said rotary shaft, saidwiper contact being biased into engagement with the unrclieved portionof the annular inner surface of both of said switch rings for electricalcontact therewith, and a collector terminal having conductor means inelectrical engagement with said collector member for making electricalcontact with the collector member, whereby rotation of said rotary shaftselectively makes and breaks electrical connection between saidcollector terminal and said first and second switch terminals inaccordance with the preselected phase relation between said switchrings.

1. A switch assembly comprising:
 1. a casing;
 2. a rotary shaft mountedfor rotation within said casing;
 3. a switch module secured with saidcasing, said switch module comprising: a. a non-conductive mounting ringmounted coaxially in said casing and having an annular rib extendingradially inwardly from the inner surface thereof, said rib having anaxially extending locating aperture therein; b. a first annular metallicswitch ring disposed in said mounting ring on one side of said annularrib, said first switch ring having an axially extending aperture formedtherein which is aligned with said aperture in the annular rib of themounting during assembly therewith; c. a second annular metallic switchring disposed in said mounting ring on the other side of said annularrib, said second annular metallic switch ring having an axiallyextending aperture formed therein which is aligned with said aperture inthe annular rib of the mounting ring during assembly therewith; d. eachof said annular switch rings having a relieved portion formed on theinner surface thereof which is positioned in a predeterminedrelationship with the relieved portion of the other switch ring byalignment of said axially extending apertures;
 4. a first switchterminal having an electrical conductor extending therefrom through thealigned axial apertures in one of said switch rings and said annularrib, said electrical conductor extending into the aperture in the otherof said switch rings and being secured in electrical contact therewith;5. a second switch terminal having an electrical conductor extendingtherefrom into electrical contact with said one switch ring; and
 6. aspring biased wiper contact carried by said rotary shaft, said wipercontact being biased into engagement with the unrelieved portion of theannular inner surface of both of said switch rings for electricalcontact therewith, and a collector terminal having conductor means inelectrical engagement with said collector member for making electricalcontact with the collector member, whereby rotation of said rotary shaftselectively makes and breaks electrical connection between saidcollector terminal and said first and second switch terminals inaccordance with the preselected phase relation between said switchrings.
 2. a rotary shaft mounted for rotation within said casing;
 3. aswitch module secured with said casing, said switch module comprising:a. a non-conductive mounting ring mounted coaxially in said casing andhaving an annular rib extending radially inwardly from the inner surfacethereof, said rib having an axially extending locating aperture therein;b. a first annular metallic switch ring disposed in said mounting ringon one side of said annular rib, said first switch ring having anaxially extending aperture formed therein which is aligned with saidaperture in the annular rib of the mounting during assembly therewith;c. a second annular metallic switch ring disposed in said mounting ringon the other side of said annular rib, said second annular metallicswitch ring having an axially extending aperture formed therein which isaligned with said aperture in the annular rib of the mounting ringduring assembly therewith; d. each of said annular switch rings having arelieved portion formed on the inner surface thereof which is positionedin a predetermined relationship with the relieved portion of the otherswitch ring by alignment of said axially extending apertures;
 4. a firstswitch terminal having an electrical conductor extending therefromthrough the aligned axial apertures in one of said switch rings and saidannular rib, said electrical conductor extending into the aperture inthe other of said switch rings and being secured in electrical contacttherewith;
 5. a second switch terminal having an electrical conductorextending therefrom into electrical contact with said one switch ring;and
 6. a spring biased wiper contact carried by said rotary shaft, saidwiper contact being biased into engagement with the unrelieved portionof the annular inner surface of both of said switch rings for electricalcontact therewith, and a collector terminal having conductor means inelectrical engagement with said collector member for making electricalcontact with the collector member, whereby rotation of said rotary shaftselectively makes and breaks electrical connection between saidcollector terminal and said first and second switch terminals inaccordance with the preselected phase relation between said switchrings.